Loads have been wrapped with packaging material by dispensing the packaging material with a packaging material dispenser, and providing relative rotation between the load and the packaging material dispenser to cover the load with the packaging material. Semi-automatic wrapping machines exist that require attachment of a leading end portion of the packaging material to the load by an operator prior to wrapping of the load. This is typically accomplished by collapsing the leading end portion into a rope, and then inserting the rope between layers of the load or tying the rope to an edge of a pallet or any suitable outcropping on the load. This attachment must be strong enough to resist a pulling force exerted by the packaging material dispenser on the packaging material during initiation of the relative rotation between the load and the packaging material dispenser. This type of attachment makes removing the packaging material difficult after the load has been shipped to its destination and is being unwrapped. Further, throughput is decreased due to the operator having to attach the leading end portion of the packaging material to each load before wrapping the load. Additionally, collapsing the leading end portion of the packaging material reduces its effective height, thus requiring the use of more packaging material to adequately cover the load.
Automatic wrapping machines typically use packaging material clamps that grip the packaging material between two opposed surfaces and use electrical or pneumatic actuators to open and close the clamps. Such packaging material clamps may be overwrapped by the packaging material during wrapping, and may create a “tenting” effect due to their distance from the load, resulting in wasted packaging material and loosely wrapped loads. Additionally, such clamps are expensive and may require costly maintenance for the electrical and mechanical actuators. Furthermore, such clamps tend to collapse the packaging material or require collapsing of the packaging material prior to clamping, thus reducing the effective height of the packaging material.
Other machines use a vacuum device that uses suction to hold the packaging material. This typically requires that the packaging material be placed in a flat manner against the vacuum device so that the vacuum device can provide its full gripping force on the packaging material. Flat placement of the packaging material is difficult to achieve. Also, the vacuum device may damage the packaging material if the suction generated is too high, while the packaging material may be pulled off the vacuum device if the suction is too low. Furthermore, the vacuum device may have difficulty gripping a roped portion of the packaging material, where the strength of the packaging material is concentrated.
The present disclosure is directed to overcoming one or more of the above-noted problems.